1 Human development is the scientific study of processes of change and stability.  The scientific study of human development began with studies of childhood during the nineteenth century.
verb (used with object), cultivated, cultivating. 1. to prepare and work on (land) in order to raise crops; till. 2. to use a cultivator on. 3. to promote or improve the growth of (a plant, crop, etc.) by labor and attention.
A cultivator is both a general term for any tool that is used to prepare soil for planting, and the name of four specific tools: a piece of machinery attached to a tractor, a small engine-propelled machine, a hand-action tool, and a traditional hand-tool.